A team of researchers from the Georgia Institute of Technology has developed a way to 3D print objects capable of expanding dramatically when heated, which could someday be used for space missions.

The process uses tensegrity (a contraction of the term tensional integrity), a structural system of floating rods in compression and cables in continuous tension. In order to create a structure that takes up little space, the researchers fabricated the struts from shape memory polymers that unfold when heated.

The struts are created using 3D printing. To enable them to be temporary folded flat, until needed, the researchers designed them to be hollow with a narrow opening that runs the length of the tube. Each strut has an attachment point on each end to connect a network of elastic cables, also 3D printed.

Once all cables are attached, the object can be reheated to initiate the transformation to tensegrity structures.

An important aspect of the structures is controlling the rate and sequence of expansion. The researchers can fine-tune how quickly each strut expands by adjusting at which temperature the transformation occurs. Thanks to this, the structures can be designed to expand sequentially, preventing entanglement.

In the video below, you can see how the structure is deployed in hot water.

The researchers think the 3D printed structures could be used for lightweight space stations, biomedical devices, or shape-changing soft robots.

Photos: Robert Felt / Georgia Tech